(CNN) -- CNN Hero Wilma Melville is helping rescued dogs find new life as rescuers themselves.
She and her nonprofit, the National Disaster Search Dog Foundation, partner shelter dogs with firefighters and train them to save lives after a disaster.
Since 1996, the group has trained 131 search-and-rescue teams around the country -- for free -- and responded to 80 disasters across the world, including the September 11 attacks and the Japanese earthquake earlier this year.
CNN's Lan Trinh recently spoke with Melville about the group's efforts.
Lan Trinh: What characteristics make a good search dog?
Wilma Melville: We look for a dog with high energy, an ability to focus. The dog has to have what we call drive. He wants a job. ...
In addition to that, he has to like other dogs (and) be affectionate with humans. He has to not care about peculiar footing under his feet, slippery stuff, moving stuff. ... He has to not be noise-sensitive. And if he is startled, he doesn't run away or freak out.
Trinh: In 1995, it could take three or four years to train a search dog and his handler. Your group has shrunk that training time to about a year. What are you doing differently?
Melville: (People) were raising puppies with the hope that the puppy would have all the characteristics needed to become a search dog. ...
I thought, "Where can I get a dog that's about a year old with the characteristics needed in a disaster search dog? Where can I get a dog like that?" And I thought, "Maybe in a shelter. Maybe the Humane Society." ...
A little math will show you that if a dog can work until he's about 10 years of age, and he's 2 or 3 when he begins his job, he has maybe six or seven years of working life. At the rate that we were producing teams in 1995, they would be retiring at the same rate we were producing them.
Trinh: Most of your search dogs come from shelters. What happens to dogs that get selected but don't have what it takes to make it through the entire training program?
Melville: If we do take a dog into our program, we say to him: "You have lifetime care, buddy. You've tried hard, but if one or two characteristics are missing and you can't make it through the six- to eight-month training, we'll provide lifetime care." This means a loving home, a good home, and staying with that home and with that dog for the lifetime of the dog.
Trinh: What personal satisfaction do you get from doing this work?
Melville: The personal satisfaction is making a huge difference in the way dogs are trained for canine disaster search plus the quality of teams that are produced.
One can accept mediocrity in a restaurant or in a retail store, but one cannot accept mediocrity in those dogs and handlers that are searching for people that are possibly alive. The window of time to locate that person alive is very small. The relief that onlookers have when a dog is searching is immense.
Trinh: Do you think you have a sixth sense for dogs?
Melville: (laughs) Certainly, I've been with dogs all my life. I don't remember a time that I didn't have a dog. But much of what I know has been learned and with the right attitude. ...
I think the dog tries much harder to understand us than we do him. We're a little behind in that area.
Read the full story on CNN Hero Wilma Melville:
To the rescue -- finding a purpose for rejected shelter dogs